1. Field of the Invention
This invention relates generally to ultrasound imaging systems, and more particularly to an ultrasound imaging system that can be delivered endoscopically.
2. Description of Related Art
Endoscopically deliverable ultrasound imaging systems are known in the art. Martin et al., U.S. Pat. No. 4,802,487, teaches an endoscopically deliverable ultrasound imaging system that includes an ultrasound probe mounted on the end of an endoscope that can be delivered by catheter. The axial or radial position of the probe is measured by a position transducer mounted on the endoscope adjacent the biopsy port from which the catheter extends. The output of the position measuring transducer is applied to the ultrasound imaging system so that the system provides an image of the tissue depth as a function of the position of the ultrasound probe. Additional examples of this technology are disclosed in Tanaka, U.S. Pat. No. 5,827,175, and U.S. Pat. No. 6,149,598.
Biomarkers are also disclosed in the prior art. The first class of prior art biomarkers include materials that have different ultrasound reflective properties and only remain in the body temporarily, eventually being reabsorbed by the body. An example of this technology is shown in Burbank et al., U.S. Pat. No. 6,161,034, assigned to SENOREX®, that teaches detectable markers that may be introduced by a cavity created by removal of a biopsy specimen to mark the location of the biopsy site so that it may be located in a subsequent medical/surgical procedure. The marker preferably includes gasses, saline solutions, or similar materials. The markers permit detection and location of the biopsy site at the first time point (e.g., up to 2 weeks) after introduction but do not interfere with imaging of tissues adjacent the biopsy site at a second time point.
Unger, U.S. Pat. No. 5,281,408 teaches a substantially homogeneous aqueous suspensions of low density microspheres which are presented as contrast media for imaging the gastrointestinal tract and other body cavities using computed tomography. In one embodiment, the low density microspheres are gas-filled. With computed tomography, the contrast media serve to change the relative density of certain areas within the gastrointestinal tract and other body cavities, and improve the overall diagnostic efficacy of this imaging method.
Unger, U.S. Pat. No. 5,334,381 teaches liposomes suitable as ultrasound contrast agents which contain media of various types including gases, gaseous precursors activated by pH, temperature or pressure, as well as other solid or liquid contrast enhancing agents. Methods of using and synthesizing the ultrasound contrast agents are also disclosed.
Klaveness et al., U.S. Pat. No. 5,676,925, teaches a gas containing, or gas generating, polymer microparticles or microballoons used as a contrast agent in ultrasound imaging.
Scarborough, U.S. Pat. No. 5,676,146 teaches a surgical implant containing a resorbable radiopaque marker that enables the position and/or orientation of the implant to be readily determined by x-ray or other radiographic technique following its surgical implantation into the body.
Smith, U.S. Pat. No. 4,909,250 teaches an animal identification system for swine or other livestock which employs an identification implant or pellet consisting of food grade material and imprinted with information to identify the source of the animal and its carcass after slaughter. The pellet is implanted under the hide or skin of the animal for purposes of identification. In the case of swine, the identification pellet is located in the fat layer of the shoulder area underneath its hide or skin. The pellet and the imprinted information consist of food grade material which is capable of being dissolved with the fat layer or disintegrated into cracklings in a rendering process. The pellet remains in the carcass after the animal is slaughtered until its removal to permit identification of the source of the animal. If the pellet is not removed, it is either dissolved with the fat of the animal or disintegrated into cracklings in the rendering process. Installation tools are disclosed for implanting the identification pellet in a horizontal or vertical orientation under the hide or skin of the animal.
Many references utilize metal reference markers that are then observed using x-rays. Example of these devices are as follows:
Kvavle et al., U.S. Pat. No. 4,007,732 describes X-ray techniques that are used to detect early evidence of breast cancer. When such evidence is found, a target is implanted in the suspect area while the patient is being x-rayed. The target has an attached line which leads from the target out through the skin of the patient. A biopsy is made with a cutting tool guided on the line attached to the target, thereby obtaining a biopsy specimen accurately centered on the suspect area.
Liprie, U.S. Pat. No. 5,282,781 teaches a composite source wire for use in treating malignant tumors within a patient's body by localized in vivo radiation with a radioactive source, via a catheter providing a path from a point external to the body to the tumor site. The source wire includes a thin continuous cylindrical flexible elongate stainless steel tube having encased therein a backbone wire running from its proximal end to a point short of its distal end to strengthen and enhance its flexibility, a cylindrical radioactive core adjacent to the distal end in abutting relation to the backbone wire, and a cylindrical plug at the distal end in abutting relation to the other end of the core, with the backbone wire, core and plug being tightly secured within the tube and the tube being securely enclosed about the plug with a tapered tip portion formed at that point. The source wire has an overall diameter sized to permit ease of movement through the catheter in advancement to the tumor site for the radiation treatment and to allow its retraction through the catheter from the point external to the body. The exterior surface of the tube is gold plated from its tip to the far end of the portion overlying the core. The source wire has an extremely small diameter (under 0.7 mm) and is sufficiently flexible that even in high radioactive dose sizes it is capable of passing through very narrow and even kinked catheters, making it useful for treating inoperable tumors such as common bile duct pancreatic cancer.
Hoffman et al., U.S. Pat. No. 4,693,237 describes marker members of radiopaque material in the form of bands each of a different geometric configuration which are sutured to the point at which a surgical graft to a blood vessel is made as in a coronary bypass operation. These ring or other shaped radiopaque members provide markers identifying the exact coronary blood vessel that the graft will lead to, each geometrical shape identifying a different coronary vessel bypassed, thus facilitating bypass graft catherization by identifying the entry point of any specific bypass graft.
Lam et al., 0 679 372 A2 teaches a radiopaque marker associated with a stent which is adapted to be implanted into a body lumen of a patient to maintain the patency thereof and a convenient and accurate method for affixing the radiopaque marker to the stent. The radiopaque marker defining an acceptable profile and capable of facilitating, under fluoroscopy, the identification of the position, diameter and length of a stent without obscuring the lesion being repaired and without impeding the deformation of an expendable stent.
Bahler et al., EP 0 146 699 A1 teaches implants consisting of contrast body and anchoring body fixed positionally secure in the bone with the aid of a structure of the anchoring body and thus form, in the bone, immovable reference points for the measurement of x-ray pictures.
Ellis, U.S. Pat. No. 5,636,255, describes a method and system for correlating accuracy of computer tomography (CT) image resolution. Small radio-opaque markers having a diameter less than one slice width of a CT scan are embedded in the object, such as a bony skeletal member, to be measured, the object is then CT scanned so that the radio-opaque markers appear in at two slices of the scan. The markers are also physically located by detecting them with a sensor, such as a positioning pointer. Also described is one form of marker comprising a tantalum sphere mounted in a ceramic, preferably alumina, pin.
Jensen et al., U.S. Pat. No. 6,181,960 B1, teaches a radiographic marker that is used to indicate a biopsy site and entry path. The marker has an arrow shape configuration with a shaft and a pair of limbs extending from the shaft at an angle of less than about 90 degrees. The tip of the arrow indicates the biopsy site and the shaft indicates the said entry path. The marker preferable is a single piece of wire, having a diameter of less than 0.010 inches, folded to four sections, to form the limbs and shaft of the arrow. Fibers can be affixed to the shaft to cause the marker to fibrose within the tissue. An introducing device, having a body and a hub, is used to insert the marker. A cannula, dimensioned to receive the body and hub of the introducing device, has a pair of receiving channels within the interior of the body to receive the limbs of the marker.
Jones, U.S. Pat. No. 4,202,349 describes a radiopaque blood vessel marker for attachment to the side wall portions of a blood vessel during, for example, a coronary by-pass operation. The markers in the preferred embodiment are flattened, oval-shaped radiopaque discs which are attached to the outer peripheral wall portion of the blood vessel at one hundred eighty degrees (180.degree.) with respect to one another (See FIG. 3). Each radiopaque marker can be comprised of a central imbedded element of radiopaque material such as tantilum which is surrounded by a suitable plastic or like resinous material which is inert and acceptable for use within the human body. During a coronary by-pass, for example, these markers could be attached by suturing or like means to the vein graft which is itself sutured into its new position during the by-pass operation. A fluoroscopic examination by a radiologist would reveal a desirable pulsation of the graft vessel in the form of the two attached markers as the radiopaque markers will constantly move (in and out) with respect to one another. Each marker is attached to the undulating wall portion of the vessel which is constantly moved when blood flow is passing through the graft as is desirable. In the event that complications arise, and the graft becomes clotted (stopping the flow of blood therethrough), a fluoroscopic examination will reveal that the radiopaque vessel markers do not move in and out with respect to one another but rather are stationary indicating a lack of undulation and a corresponding lack of blood flow.
Elliot et al., U.S. Pat. No. 4,041,931 relates to split ring markers fabricated in whole or in part from a radiopaque material, usually metal, having the terminal ends thereof and a medial portion formed to define eyelets by means of which said marker can be sutured to the tissue at the sight of an anastomosis to provide a visual indication of its location when examined fluoroscopically.
Foerster et al., U.S. Pat. No. 5,902,310 teaches an implantable marking device which is designed to percutaneously deliver permanent markers to desired tissue locations within a patient's body, even if the desired locations are laterally disposed relative to the distal end of the delivery device, as is the case for conduit or cavity walls. This provides several advantages to the physician in diagnosis and management of tissue abnormalities, such as a means of localization of a tissue abnormality for follow-up surgical treatment, and a means of tissue abnormality site identification for purposes of ongoing diagnostic follow-up. In one preferred construction, a radiographic clip is configured in the form of a surgical staple. A disposable tissue marker applier, which comprises a flexible tube, pull wire, and squeeze handle, is employed to advance and deploy the clip to a desired tissue location. Either a flexible or a rigid introducer is also provided for providing access to the site to be marked.
Morris, U.S. Pat. No. 4,331,654 describes a drug carrier formulation consisting of magnetically-localizable, biodegradable lipid microspheres.
Granov et al., U.S. Pat. No. 5,236,410 describes a method of treatment of a tumor comprising the steps of catheterization of the arterial vessel that feeds the tumor, and transcatheter administration of a suspension of magnetically hard ferromagnetic material in an oil solution of an oil-soluble antitumor substance with simultaneous application of local magnetic field onto the area of the tumor. After 1–3 days the tumor is subjected to ultrahigh radio frequency electromagnetic field or ultrasonic waves to produce heating of the tumor tissue to the temperature of 43.0.degree.–43.5.degree. C. for a period of 5–45 minutes.
Tournier et al., U.S. Pat. No. 5,668,490, teaches suspensions of either echogenic or magnetic particles in aqueous bioadhesive carriers that effectively improve imaging by echography, respectively NMRI, of the digestive tract. Affinity of the compositions for the gastric mucosa can be adapted to the needs by appropriately selecting the carrier in function to inherent bioadhesive capacity: this technique leads to improved visualization of selected portions of the lumen.
Additional patents of interest include Dowlatshahi, U.S. Pat. No. 5,853,366, which describes a marker element which is made of radiopaque material and includes at least two leg portions of approximately equal length connected at an angle relative to each other to form a generally V-shaped resilient member that is capable of being positioned wholly within the body of a patient. A localizing device and method using the marker element for marking a tissue mass of interest are also provided. The device and method include an elongate guide member, such as a cannula, having a first end that is inserted into the body so as to be directed toward a position proximate the tissue mass of interest and an opposite second end that extends from the body. A guide path extends between the first end and the second end of the guide member. The marker element is introduced into the second end of the guide member using a marker element dispenser and then urged along the guide path using a stylet or similar prodding member. The marker element collapses to a reduced size while being urged along the guide path, and substantially resumes its original V-shape upon discharge from the guide member so as to remain in a fixed position wholly within the body without irritating or traumatizing the surrounding tissue. A plurality of marker elements may be positioned in a similar manner to mark the tissue mass of interest.
Wichterle et al., U.S. Pat. No. 3,818,894 teaches an implant for surgical purposes which is especially useful for the operative treatment of the afflicted vocal cords, as well as to the method for its production. The implant is made from a physiologically inert material that swells in the presence of water, such as a synthetic cross-linked hydrophilic gel, and has in a dry state, when it is ready for use in an operation, the shape of a straight or bent stick provided with a sharp, pointed tip. The implant body except the tip may contain physiologically inert plasticizers.
Tucci, U.S. Pat. No. 4,545,367 teaches a detachable balloon catheter assembly which comprises a balloon and sealing valve assembly including a sealing valve being formed of a resilient material having an elongate passageway extending therethrough and being mounted in a sleeve, an inflatable balloon having a mouth portion which is bonded to the sealing valve, and a small diameter cannula having a distal end which extends through the passageway in the sealing valve. The small diameter cannula includes a connector terminal on the proximal end which is adapted to be coupled to a source of fluid pressure. The passageway in the sealing valve takes the form of an elongate slit prior to insertion of the small diameter cannula through the passageway, and upon insertion of the cannula through the passageway, the passageway takes the form of a cylindrical aperture which is in fluid-tight engagement with the outer surface of the cannula while allowing the cannula to easily slide through the passageway. When the balloon is inflated to a desired size, the cannula may be withdrawn from the passageway in the sealing valve thereby causing the passageway to revert to the slit configuration in order to provide a fluid-tight seal for the inflated balloon. In one embodiment, a piston is mounted on the small diameter cannula and an aperture extends through the side wall of the cannula so that a burst of fluid pressure may be applied to the piston causing it to be driven away from the sealing valve to drive the cannula out of engagement with the sealing valve for detachment of the cannula from the inflated sealed balloon.
Barlow et al., U.S. Pat. No. 5,422,730 describes a method and apparatus for optical detection and imaging of regional circulatory flow in biological tissues for research purposes. An animal or plant organ is perfused with a saline suspension of colored and/or fluorescent microspheres. The organ is excised and fixed in the form of a specimen block for mounting in a microtome or other suitable apparatus. Under automatic control of a microcomputer equipped with a frame grabber, a surface layer of the block is removed, the resulting new exposed surface of the block receives a flash of illumination from a light source, and light reflected by colored microspheres or, alternatively, light emitted by fluorescent microspheres, is detected by a CCD video camera aimed at the block. Also under microcomputer control, light filters having suitable light bandpasses are interposed between the light sources and the block, and between the block and the camera. Video signals are converted by the microcomputer into position coordinates with associated optical intensities from which regional circulatory flow is computed and displayed on a monitor.
Other references of interest include Leeb et al., U.S. Pat. No. 5,643,246, Ahmed, U.S. Pat. No. 4,647,480, Klaveness et al., U.S. Pat. No. 5,676,925, Miller et al., U.S. Pat. No. 6,481,685, Chapelon et al., WO 93/14712, WO 96/08208, and Foerster et al., WO 98/06346.
The above-described references are hereby incorporated by reference in full.